Announced on January 26, a US philosopher raises questions on whether or not teaching little girls to be clean and tidy is negatively affecting their health in the long run, raising their risks of asthma, allergies, and autoimmune disorders such as Crohn's disease and rheumatoid arthritis.

In a new study published in the journal Social Science and Medicine, Oregon State University philosopher Sharyn Clough points out that women have higher rates of all of these illnesses, yet no one knows why.

"Girls tend to be dressed more in clothing that is not supposed to get dirty, girls tend to play indoors more than boys, and girl's playtime is more often supervised by parents," said Clough. "There is a significant difference in the types and amounts of germs that girls and boys are exposed to, and this might explain some of the health differences we find between women and men."

A recent Harvard University study found that being too clean is bad for a child's health, and that exposure to bacteria could help prevent asthma.

The US Centers for Disease Control and Prevention notes that asthma prevalence is higher among females. Also, the National Institutes of Health statistics show that autoimmune diseases strike women three times more than men.

Clough adds that a simple solution is to encourage outdoor playtime, for both girls and boys, even if that means your kid gets dirty. "Getting everyone, both boys and girls, from an early age to be outdoors as much as possible is something I can get behind," she said.